1. Technical Field
The present invention relates to a liquid injection device which injects a liquid from a nozzle to incise or excise a living tissue.
2. Related Art
A liquid injection device which injects a liquid such as water or physiological saline solution toward a living tissue and thus incises or excises the living tissue is developed. In a surgical operation using such a liquid injection device, only a tissue of an internal organ or the like can be selectively incised or excised without damaging nerves and blood vessels. Therefore, the burden on the patient can be reduced.
Also, a liquid injection device which injects a liquid in a pulsed manner instead of continuously injecting a liquid from a nozzle and thus can incise or excise a living tissue with a small amount of injection is proposed (JP-A-2008-82202). In this liquid injection device, a liquid is supplied to a liquid chamber using a supply pump and the volume of the liquid chamber is reduced to pressurize the liquid, thus injecting the liquid from a nozzle in a pulsed manner.
These liquid injection devices have an injection unit (hereinafter referred to as an applicator) in which a nozzle for injecting the liquid is formed and which an operator holds in his or her hand to operate, a supply pump for supplying the liquid to the applicator, a connection tube connecting the supply pump with the applicator, and the like. Also, a liquid chamber connected to the nozzle, an actuator which deforms the liquid chamber to reduce the volume of the liquid chamber, and the like are provided within the applicator of the liquid injection device which injects the liquid in a pulsed manner.
However, such a liquid injection device has the following problem. That is, in the applicator, the inside liquid contacts the outside air at the part of the nozzle. Therefore, if the absence of injection of the liquid continues, the outside air may enter the inside of the applicator from the part of the nozzle. Consequently, there is a problem that various bacteria can propagate within the applicator over a long period of time.